Received: 25 February 2021
Accepted: 13 May 2021
First Online: 1 June 2021
: The institutional review board at the Tokyo University hospital approved this retrospective study (No. 2674). Patients and their families were informed that the data from their cases would be submitted for publication, and all provided written, informed consent. All methods were performed in accordance with the relevant guidelines and regulations.
: All authors agree to the publication of this article.
: No potential competing interest relevant to this article was reported.